ERCP stands for endoscopic retrograde cholangiopancreatography!  It is carried out for the investigation of patients with jaundice or suspicion of bile duct disease.  Intravenous sedation and X-Rays are also used during the test.  Sometimes biopsies are taken and sometimes treatment can be given such as inserting stents or removing bile duct stones.  ERCP cannot remove stones within the gallbladder which instead require surgery to remove the gallbladder containing the stones.